Different Types of Prototypes

• Paper sketches: This is the lowest level of prototype. If you can wield a pencil, you can manage! Draw out a basic idea of what your user interface will look like. If you want to make something visually appealing to communicate to investors/stakeholders, work with a designer to create something that fits your vision.
• Digital prototypes: You can also create a working mock-up of your envisioned product, and there are many tools to help you do so.

The rule of thumb when picking prototyping tools is their complexity.